This invention relates to gas turbine engines for aircraft and means for reclaiming surplus fuel captured in the fuel manifold system incident engine shutdown.
This invention serves to solve the problem described in U.S. Pat. No. 3,841,089 granted to Herbert Clark on Oct. 15, 1974. As noted this patent describes a system that reclaims surplus fuel by collecting the fuel trapped in the fuel lines (nozzles, manifold, valve, etc.) upon the engine shutdown and inserting the fuel back into the fuel system by the continuous operation of a jet pump motivated by fuel upon starting the engine. However, the system described in U.S. Pat. No. 3,841,089, supra, incurs two distinct situations which may not in certain applications be tolerable. These are (1) the heat added to the fuel occasioned by the continuous operation of the injector pump and (2) the size of the drain tank which is dictated by the flow capacity of the jet pump and the amount of surplus fuel needed to be stored. If the engine is stopped and restarted a number of times for any of a number of reasons, as say for an abortive take-off and the capacity of the pump does not permit complete emptying of the drain tank in the allocated time, hence, the drain tank must be large enough to accommodate additional surplus fuel collected in the fuel system upon additional shutdowns. Obviously, repeated number of stop-go situations contemplated would dictate the storage capacity and 2 or 3 or better such go arounds are not unusual.
We have found that we can obviate the problems noted above, completely eliminate the jet pump and reclaim surplus fuel by a system that is characterized as being automatic, repeatable, and relatively simple with a relatively small drain tank, sized sufficiently cterized as being automatic, repeatable, and relatively simple with a relatively small drain tank, sized sufficiently to remove only the surplus fuel trapped in the fuel system for one stop-go situation. In addition this invention affords the following advantages to name but a few:
The system is completely isolated from the engine fuel system during all ground and flight operation of the aircraft.
The system is independent of and requires no alteration of the engine fuel system and/or starter.
The unit provides visual indication of whether or not the operation of waste fuel disposal system is satisfactory.